In the pursuit of a developable form of a solid, orally-administered pharmaceutical compound, a number of specific features are sought. Although an amorphous form of a pharmaceutical compound may be developed, compounds having high crystallinity are generally preferred. Often such highly crystalline compounds are salts.
International Publication Number WO 2004/046092 describes a series of compounds which are indicated as antagonists of the CCR9 receptor, and which are indicated as being useful in the treatment of CCR9-mediated disorders. Specifically disclosed in that application is the compound 4-tert-butyl-N-[4-chloro-2-(1-oxy-pyridine-4-carbonyl)-phenyl]-benzenesulfonamide (hereinafter “Compound A”). Identification of a stable, crystalline form of such compound with suitable properties for oral administration would be highly desirable for the treatment of CCR9-mediated diseases.